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What is the difference between SQL, PL-SQL and T-SQL?
... management systems: SQL Server, Oracle, MySQL, PostgreSQL, DB2, Informix, etc.
PL/SQL is a proprietary procedural language used by Oracle
PL/pgSQL is a procedural language used by PostgreSQL
TSQL is a proprietary procedural language used by Microsoft in SQL Server.
Procedural languages are design...
How can I use interface as a C# generic type constraint?
...
{
SomeClass<IMyInterface> myMember; // or a property, method, etc.
}
Basically this involves scanning all types, inheritance, members, parameters, etc, etc, etc. If a type is a generic type and has a constraint, we check the constraint; if it's an array, we check the element type.
A...
postgresql port confusion 5433 or 5432?
...
/etc/services is only advisory, it's a listing of well-known ports. It doesn't mean that anything is actually running on that port or that the named service will run on that port.
In PostgreSQL's case it's typical to use port...
How to profile a bash shell script slow startup?
...another version that can output nanoseconds), do this at the beginning of /etc/bash.bashrc (or wherever you'd like to begin a trace in any Bash script):
PS4='+ $(date "+%s.%N")\011 '
exec 3>&2 2>/tmp/bashstart.$$.log
set -x
add
set +x
exec 2>&3 3>&-
at the end of ~/.bas...
Why is the default value of the string type null instead of an empty string?
...r null before I can safely apply methods like ToUpper() , StartWith() etc...
14 Answers
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AWS Difference between a snapshot and AMI
... of specific EBS volume, it might be any volume (Root volume, data volume, etc.)
AMI (Amazon Machine Image) is a backup of Entire EC2 instance. For example, with proper configuration it's possible to create AMI which includes multiple EBS volumes.
Now, it might sound confusing, but they are both s...
Just what is Java EE really? [closed]
...scanned only once for all your classes instead of every library (EJB, JPA, etc) doing this scanning over and over itself. Also because of that, CDI annotations can be applied to EJB beans and JPA entity managers can be injected into them.
Why do I need something massive as JBoss just to compile sim...
What are the most common naming conventions in C?
...typically are in lower case (in my experience) rather than the C++/Java/C#/etc convention of making the first letter a capital but I guess it's possible in C too.
C++ is more complex. I've seen a real mix here. Camel case for class names or lowercase+underscores (camel case is more common in my ex...
Difference Between Invoke and DynamicInvoke
...er! If you just know that it is Delegate, it has to resolve the parameters etc manually - this might involve unboxing, etc - a lot of reflection is going on. For example:
Delegate slowTwice = twice; // this is still the same delegate instance
object[] args = { i };
object result = slowTwice.Dynamic...
How to install JSTL? The absolute uri: http://java.sun.com/jstl/core cannot be resolved
...ase you're actually using a normal Java EE server such as WildFly, Payara, etc instead of a barebones servletcontainer such as Tomcat, Jetty, etc, then you don't need to explicitly install JSTL at all. Normal Java EE servers already provide JSTL out the box. In other words, you don't need to add JST...